唯識二十論述記 2.268

2.268

Commentary: This explains the first line of the verse. Among the four indeterminate [mental factors], the sleep caitta can cause a sentient being's bodily constituents to become heavy and the mental constituents to become dull; the mind in a sleep-dream is impaired by this, and because it makes the mind dull, its deliberation is not distinct and its power is feeble and inferior. As for the waking mind, since it is not impaired by sleep, it apprehends objects clearly and its power is increased and strong, unlike in the dream state. In madness, intoxication, and the like, the mind impaired by conditions is similarly feeble and inferior. This merely answers the question regarding the mind in the dream state.